Find a more general replacement for class PrettyPrint from SAWScript.AST

[brianhuffman]

Module SAWScript.AST (which includes pretty printing functions for the AST datatypes) defines a class PrettyPrint with a function pretty :: Int -> a -> Doc:

saw-script/src/SAWScript/AST.hs

Lines 348 to 349 in 14bab8f

	class PrettyPrint p where
	pretty :: Int -> p -> PP.Doc

As @kquick points out (#931 (comment)), this definition is a bit confusing, considering that other prettyprinting libraries define a very similar class with a similarly-named function that has a different type:

class Pretty a where
  pretty :: a -> Doc

It doesn't appear that class PrettyPrint is used anywhere else in saw-script at the moment. However, a type class for pretty-printing with precedences might be quite useful if it was standardized, given function names that don't conflict with other pretty printing libraries, and maybe put into a separate package so that it could be used across multiple projects.

[brianhuffman]

I should point out that cryptol defines the following class in module Cryptol.Utils.PP, which is another implementation of the same idea:

class PP a where
  ppPrec :: Int -> a -> Doc

(This uses a Doc type from the HughesPJ pretty library, however; in order to be widely used across the SAW ecosystem, it would need to use the prettyprinter Doc type.)